How to use a thermometer correctly? These are the most frequent errors

The thermometer is one of the basic medical devices that, according to the experts, must always be present in the basic medicine cabinet of any home. With this we will know if we have fever or not, something important because this symptom is indicating that our body is being the victim of an infection. This is actually a defense mechanism that the body uses to protect yourself from these microorganisms and fight against them not in your favor.


Normally the body is kept at a constant temperature that is regulated through a system located in the hypothalamus of the brain. Throughout the day this may vary slightly. Usually first thing in the morning it’s lower and it reaches its peak between four and six in the afternoon, so that it is possible to have even slightly more than 37 degrees. It is considered a low-grade fever if it reaches 38 ºC, and fever when this number of degrees is already exceeded.

The appearance of fever manifests itself in different ways in people, in some cases it arises headache, muscle or joint pain, and drowsiness. If you have chills, the body is warning us that a rise in temperature is taking place.

The best way to find out if we have a fever and control it at the same time is use the thermometer. But do we know how to use it well? A few years ago mercury thermometers were used, however these were discarded due to the danger they entailed. If they were broken, the mineral inside it could be inhaled, and as is well known, it is a toxic substance that is harmful to humans.

Today the thermometer that tends to predominate in homes is the digital one. This is a small, easy-to-use device with a window showing degrees. Its reading is fast, since normally in less than a minute it already tells us the temperature we have. Its operation is based on electrical heat sensors that provide us with the required information.

Digital thermometer

Mouth, armpit and rectum

These devices can be placed in the mouth, under the armpit and in the rectum. In all these places you have to know how to position them correctly to avoid giving an inaccurate figure.

Before proceeding to the measurement in any of the assumptions that we have chosen, we must prepare the digital thermometer properly. In order not to fall into errors of use, the first thing we should do is read the instructions. The operation of these devices is usually similar. In general, the power button is usually next to the digital window and to activate it you only need to press on it.

The first thing that usually appears is the last reading, so we will have to remove it. The mechanism of each brand is different, but the normal thing for this to happen is to keep pressed the power button a few seconds. Then the figure disappears and is replaced by a letter or two lines, each device is different. Only when the screen no longer has the previous reading and as specified in the instructions can we use it again.

Its placement is the armpit is very simple. It is simply a matter of putting the bulb or metal part under the armpit and press the arm against the body. Then you just have to wait for it to beep. When we remove it, we will read the degrees we have.

It also can place in the rector, although this formula is used more in the case of babies and children. Before placing it, it can be lubricated with petroleum jelly and introduced into the area, reaching a maximum depth of 1 to 1.5 cm. Again we will have to wait for the device to beep.

The last alternative is to put it in your mouth. Here you have to place it under the tongue and close the mouth. While we wait we have to breathe normally through the nose. To hold it well, the lips must remain fixed and together. We will have to hold on like this until the device warns us.

Woman with thermometer

Ear and forehead

Other less common types of thermometers in homes are digital ear. These measure the temperature inside the ear canal and must be carefully inserted into the ear canal, holding them steadily until the measurement process is complete. In this case, it is vital that the area is well free of earwax because otherwise it will interfere with operation.

The infrared ear and forehead thermometers They are another of the alternatives that exist in the market, although they are not usually had at home because their cost is higher. They are sensitive to magnetic fields and humidity, so that when making the measurement we should not be near mobile phones, televisions and other electrical appliances.

It is important that acclimatize to the room where the measurement is to be made, so it is advisable to leave them on for at least fifteen minutes beforehand. When measuring the forehead with this type of thermometer it is important not move the slightest for the seconds that the infrared measures your forehead.